Mouthpiece Ventilation in Patients with Neuromuscular Disease: A Brief Clinical Review

Nicolini A, Russo D , Barlascini CO*, Sclifò F^§, Grecchi B^{^}, Garuti GC°, Banfi PI°°

Respiratory Rehabilitation Unit and ALS Centre, Italy

*Public Health Department, Italy

^§ Allergy & Respiratory Diseases Clinic, University of Genoa, Italy

^{^}Physical Medicine and Rehabilitation, Italy

^°Pulmonary Department Santa Maria Bianca, Italy

^°°Don Gnocchi Foundation IRCSS, Italy

*Corresponding author: Nicolini Antonello, Respiratory Rehabilitation Unit and ALS Centre, Italy

Received: July 31, 2014; Accepted: September 22, 2014; Published: September 25, 2014

Abstract

The Open-circuit Mouthpiece Ventilation (MPV) is a mode of ventilation that uses a mouthpiece interface which the patient holds with the lips when he wants to be supported during inspiration. There exists a poor understanding of this method's benefits compared to other modalities. Non-invasive ventilation (NIV) is sometimes reported as suboptimal in neuromuscular disease patients due to excessive secretions in the airways , hypercapnia due to inadequate ventilator settings , or because of a lack of tolerance of the interface. Interfaces that cover the nose and / or mouth and nose are the most commonly used, but may cause skin lesions and claustrophobia. Many of these drawbacks can be avoided by using a mouthpiece to administer the NIV. The MPV is used by many patients as daytime ventilatory support in combination with other modes of ventilation interface effective for night ventilation. There are two models mouthpiece of different sizes 15 and 22 mm .NIV has been used for years in patients with neuromuscular disorders as a viable alternative to continuous ventilatory support via tracheotomy tube. NIV is associated with a reduced risk of pneumonia and other respiratory complications. Its use in the volumetric mode allows air-stacking to improve cough. The mouthpiece interface facilitates speech and swallowing, factors that lead to a better quality of life for patients. This review aims to highlight the indications, along with the advantages and disadvantages of MPV.

Keywords: Non-invasive ventilation; Mouthpiece; Open-circuit mouthpiece ventilation (MPV); Neuromuscular disease; Ventilator settings

Introduction

Neuromuscular diseases represent a heterogeneous group of disorders of the muscle, nerve, and/or some neuromuscular junction. The respiratory muscles are rarely spared in neuromuscular diseases even if the type of muscle involvement, severity, and time course greatly varies among the different diseases [1]. The most common neuromuscular diseases in childhood are Duchenne muscular dystrophy (DMD), spinal muscular atrophy (SMA ) and congenital myophathy, congenital muscular dystrophy ( CMD ) . In adults, amyotrophic lateral sclerosis, myotonic myopathy (Steiner's disease) and limb-girdle muscular dystrophy (LGMD) are the most common neuromuscular diseases which can benefit from NIV treatment according their progressiveness are reported in the Table 1[2].Before 1953, the non-invasive ventilation (NIV) was practiced through the use of negative pressure ventilators : "iron lung ","armor". Despite of their great success as a continuous ventilator support, ventilation through tracheotomy became the standard since the epidemic Danish polio in 1952, because it was possible to move patients and secretions could be easily managed [3]. In 1953 patients who used lungs steel or armor began to use the ventilation mouthpiece during the day. In the United States intermittent positive pressure ventilation (IPPV) through a mouthpiece has been the accepted practice for patients requiring continuous ventilatory support as an alternative to mechanical ventilation via a tracheotomy tube [3]. The portable ventilator manufactured by Bantam Harris Thompson in 1956 was another turning point. Mouthpiece use slowly grew in patients with severe ventilatory defect due to restrictive illnesses (vital capacity lower than 500 ml) and with inefficient cough [3]. The result was a reduced dependence on the ventilator with less hyper secretion [3, 4]. Non invasive ventilation via mouthpiece was used in 257 patients requiring continuous ventilatory support at the Goldwater Memorial Hospital from 1968 to 1987 with excellent results. [5]. Despite remarkable results by Dr. JR. Bach's group [ 3,4,5 ], few centers in the United States used the ventilation via mouthpiece in neuromuscular patients .Until ten years ago there were only sporadic reports of NIV mouthpiece in this patient group whose numbers have continued to increase with time. Server a et al [6] and Toussaint et al. [7, 8] changed this.

Table 1: Neuromuscular diseases can benefit fron NIV according the progressiveness of respiratory impairment.




  
    Spinal muscular atrophy (SMA)� Type 1
    Rapid worsening (    0-3 years )
  
  
    Spinal muscular atrophy Type 2
    Slow worsening    (>15 years)
  
  
    Spinal muscular atrophy Type 3
    Slow worsening    (>15 years)
  
  
    Acid maltase deficit
    Slow worsening    (>15 years)
  
  
    Duchenne dystrophy (DMD)
    Intermediate    worsening ( 5-15 years )
  
  
    Myotonic dystrophy�    (Steinert's disease)
    Intermediate    worsening ( 5-15 years )
  
  
    Limb girdle muscular dystrophy
    Intermediate    worsening ( 5-15 years )
  
  
    Amyotrophic lateral sclerosis (ALS)
    Rapid worsening (    0-3 years )



Table 1:  Neuromuscular diseases can benefit fron NIV according the progressiveness of respiratory impairment.

The Fundamentals

NIV improves gas exchange, relieves shortness of breath, allows inspiratory muscles to rest, reduces the incidence of nosocomial infections. Mortality from and hospitalizations for respiratory failure decrease. [9] The great limitation of this technique is that it is impossible to implement on a chronic basis if the interface is uncomfortable [ 10,11 ]. Fortunately, now there are over 100 types of interfaces. The most frequent causes of NIV failure with consequent intubation of patients are due to inappropriate settings of the ventilator. The group treating these patients has to be experienced. Skin breakdowns due to pressure points of interfaces must be prevented. Strict skin care protocols are essential .Misuse of mechanically assisted coughing (MAC) to eliminate airway secretions [ 10, 11, 12 ] must be prevented. However, the failure of NIV may also occur due to a serious bulbar dysfunction, or a severe cognitive deficit involving a lack of cooperation in the maneuvers of assisted cough, or due to the inappropriate administration of sedative drugs or additional oxygen [ 12,13]. These latter problems are harder to overcome. For these reasons the choice of the appropriate interface is crucial for the NIV success [14]. Being able to switch between different types of interfaces to change the pressure points of the mask on the skin can help to increase patient adherence to NIV [14]. However, few clinical trials have compared effects produced by different types of interfaces on clinical outcomes; none has evaluated the impact of interfaces on the respiratory workload [15, 16].

Rationale for the Use of Ventilation with Mouthpiece (MPV)

Nasal and oro-nasal masks are the most practical as well as the most commonly used for the administration of NIV, especially during sleep [14, 17, 18 ]. They permit ventilation through the nose or nose and mouth: they would be perfect interfaces if their use was not limited by claustrophobia, discomfort and skin lesions [ 14, 18, 19 ]. Nasal interfaces also include nasal pillows: they have the advantage of producing no skin lesions and claustrophobia, but they have the disadvantage of higher air leaks when high inspiratory pressure is administered[ 14,18 ]. Currently tracheotomy is widely offered to patients affected by neuromuscular diseases who need 24 hour assistance; mouthpiece NIV has been the alternative. Tracheotomy may increase costs, complications, and social isolation [20]. When the choice is given, to them, patients usually prefer non-invasive ventilation [21]. Patients with neuromuscular diseases who are usually ventilated during the night with nasal or oronasal masks, but they may have a level of inspiratory muscle weakness that requires continuous ventilation. The application of an oro- nasal interface can interfere with social interaction; impair eating, drinking, and talking. This mask changes a patient's perception of him/herself. This last may have drastic consequences psychologically. The use of angled mouthpieces wired by a metal flexible arm support (if the patient has no strength to keep the mouthpiece near to the mouth) is the ideal solution for daytime ventilation in patients who can still grab mouthpiece with preserved neck movement and hold it in mouth . The open-circuit mouthpiece ventilation, has been reported to be safe and comfortable in patients confined to wheelchairs. In the selected patient, it's easy to apply and to use even during daily living activities such as eating and talking [22, 23 ]. Despite these obvious advantages, this modality is not commonly used. However its effectiveness in improving long-term survival has been documented in a series of more than 500 neuromuscular disease patients who required continuous ventilatory support [23]. Tracheotomy is considered mandatory for the survival of patients who have severe bulbar dysfunction and high risk of recurrent and massive aspiration pneumonia. Its utility for neuromuscular patients without bulbar impairment is not conclusively proved regardless of severity of ventilator failure [24, 25, 26]. It must be stated that there are no published evidencebased guidelines concerning mouthpiece ventilation. Its application is mainly based on the experience of few centers [20. 21, 22, 23 ]. Patient selection is of paramount importance. Match the technology with the patient; be ready to change the technology as is required by the patient's changing condition. Obviously, randomized controlled studies pose enormous practical and ethical problems. Mouthpiece ventilation is more comfortable compared to nasal or facial masks, but it requires a more active participation of the patient and a longer initial training period for the staff to teach the patient how to use it. However, in the long term, it has the following significant advantages [1, 3]:

Less negative psychosocial impact on patient
no risk of pressure breakdown on the face
Better speech than with the oro-nasal and nasal mask
Better ability to eat and drink
Improved image of the self
Improved security (compared to tracheotomy)

It permits the use of glosso-pharyngeal breathing in case of sudden failure of the ventilator or accidental disconnection from the ventilator [20, 21, 22, 27 ]. This last advantage can save lives. There are various types of mouthpiece for non invasive ventilation [14]. The angled mouthpiece is more commonly used, because they are easier for the mouth to grip. There are 2 types of angled mouthpiece, one of 15 and one of 22 mm (Figure 1). In full-time ventilator users, daytime ventilation with angled mouthpiece in combination with nasal or oro-nasal mask ventilation during the night (or in selected patients, the use of a standard nozzle or of an orthodontic bite with a custommolded flange covering the lips for use of the mouthpiece, rather than a mask) during the night offers a better life [22].With the mouthpiece any mode of ventilation including the pressure assisted ventilation mode can be used (e.g., closed system with the continued support of the interface on the mouth). During the day, particularly when the patient is sitting, a system in which the mouthpiece should be placed to close to the mouth by adjustable arm and the patient can grab the mouthpiece as desired, close to the mouth by an adjustable arm. It should be removable for talking, eating, or breathing independently. In this case the volumetric ventilation appears the most suitable because the flows provided are slow and steady; it also allows airstacking maneuver [28, 29, 30]. Recently special software for the open mouthpiece ventilation that facilitates the setting of alarms with a system of triggering dedicated to this mode which facilitates its use, by activating the emission of air only by the positioning of the patient's lips on the mouth piece has come on the market; this software has been tested with good results in selected patients and is commonly known as "kiss the trigger ". [ 17, 31, 32, 33 ] .

Figure 1: 22 and 15 mm angled mouthpieces with adaptors.

    
    
    Figure 1:  22 and 15 mm angled mouthpieces with adaptors.

Advantages, Disadvantages and Side Effects of Ventilation with Mouthpiece

The most significant advantage compared to a nasal or oronasal mask is that mouthpiece produces less interference with speech, better appearance, and absence of claustrophobia. The greatest disadvantage is the difficulty of use at night [ 22, 34 ]. Other disadvantages are air leaks from the mouth or nose [ 1, 14, 32, 34 ]. Moreover, the mouthpiece may cause gastric distension , even salivation and even more rarely vomiting [14]. Often these "non-nocturnal problems can be fixed. The failure of the MPV and /or NIV is seen: a) if patients are not cooperative, or b) more often, in the presence of a severe bulbar dysfunction, unable to cooperate. If the combination of NIV, interface, and MAC fails to maintain a constant oxygen saturation between 94 - 95%, tracheotomy should be considered.

Ventilator Types, Settings, and Settings for the Ventilation Open-Circuit Mouthpiece

The mouthpiece ventilation is usually performed using portable ventilator in volume assisted - controlled mode (ACV) [32 ] to provide adequate ventilatory support and allow the patient to perform air -stacking maneuvers. Volumetric mode allows the patient to choose at every inspiration the amount of air which they want to inhale, adjusting the seal with the lips on the mouthpiece. A tidal volume between 700-1500 ml for adult patients ( depending on the amount of air the patient wants to let enter the mouth ) , ensures proper ventilation: so that he/she can even talk, shout or cough [ 17,31,32 ] . Moreover, the maneuver of air -stacking is done by taking a series of breaths at high tidal volume without exhaling , trying to get an air volume approaching the total lung capacity to make cough as effectively as possible [ 23,31,32 ] .In this way , a patient who has a ineffective cough can often produce a peak flow sufficient to eliminate secretions through an "air-stacked cough" [ 26 ] . Some home ventilators was tested for delivering MPV [ 31,36 ]: among them Trilogy (Philips Respironics ) has a dedicated particular function called MPV "Kiss -trigger " (see above) as well as an arm dedicated to support the mouthpiece to facilitate its use [ 36 ]. The pressure modes are usually shut off because of the high flow that the devices continue to deliver when the patient is disconnected to the mouthpiece and because they do not permit air -stacking [28,31,32,37,38].In the new generation ventilators manufactured by Philips - Respironics one must not set a positive expiratory pressure ( EPAP or PEEP) ( set it to Zero PEEP or ZEEP ) .The alarms for apnea, minimum pressure, and minimum volumes can easily be shut off in order to avoid their unnecessary activation. In most home volumetric ventilators the minimum pressure alarm cannot be excluded; therefore it is necessary to set up a PEEP (often 2 cm H2O ) , which, thanks to the resistance to the flow of air created from the angle of the mouthpiece creates a pressure that prevents the continuous activation of the alarms. The most common mode of ventilation is ACV with a tidal volume between 0.7 and 1.5 L without PEEP ( EPAP ) , alarm with low set pressure to minimum possible or excluded , and the maximum apnea time [ 17,32 ] (see Table 1) [38]. The patient activates the breath by putting the mouth on the mouthpiece and creating a small negative pressure in the circuit as drinking or inhaling from the mouthpiece (Figure 2). With the "Kiss trigger", ventilation is activated when the patient simply leans the mouth on the mouthpiece; no other effort is required for the patient [36, 38] . Sometimes volume cycling ventilation produces gastric distention; in these cases, one switches to pressure cycling ventilation [32, 33, 37, 38].

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Citation: Nicolini A, Russo D , Barlascini CO, Sclifò F, Grecchi B, Garuti GC, et al. Mouthpiece Ventilation in Patients with Neuromuscular Disease: A Brief Clinical Review. Phys Med Rehabil Int. 2014;1(3): 4. ISSN:2471-0377

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Spinal muscular atrophy (SMA)� Type 1	Rapid worsening ( 0-3 years )
Spinal muscular atrophy Type 2	Slow worsening (>15 years)
Spinal muscular atrophy Type 3	Slow worsening (>15 years)
Acid maltase deficit	Slow worsening (>15 years)
Duchenne dystrophy (DMD)	Intermediate worsening ( 5-15 years )
Myotonic dystrophy� (Steinert's disease)	Intermediate worsening ( 5-15 years )
Limb girdle muscular dystrophy	Intermediate worsening ( 5-15 years )
Amyotrophic lateral sclerosis (ALS)	Rapid worsening ( 0-3 years )